This research tested the effects of system reliability information and interface features on human trust and reliance on individual combat ID systems. Experiment I showed that participants had difficulty in estimating the reliability of the ‘unknown’ feedback from these systems. Providing the reliability information led to appropriate reliance on that feedback. Experiment II showed that participants’ trust in the ‘unknown’ feedback was influenced by the system’s activation mode and the ‘unknown’ feedback form, but their reliance on ‘unknown’ feedback was not affected. In addition, a new method was proposed to measure reliance on automation. This measure was used effectively in both experiments, and demonstrated several advantages over previous methods. Finally, implications for the design of interfaces for individual combat ID systems and the training of infantry soldiers were drawn from the results of the studies.